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A late exit from the breeding pond

Last week I received an e-mail from Luke Ormand, an environmental analyst with the Town of Brookhaven who has worked on conservation projects involving some of Long Island’s mole salamanders, specifically spotted and tiger salamanders. Attached to the e-mail were several photos taken over Labor Day weekend of salamander larvae from a Southampton site. Luke could not positively identify most of the larvae; those that he could were spotted salamanders.

He needed help identifying the rest.

Identifying the larval forms of salamander species—as well as many other wildlife species—is difficult. Even some of the experts prefer to wait until they metamorphose into their adult forms before making appositive ID. That can be done by periodically revisiting the pond, or in this case, permission was granted to take six individuals to the South Fork Natural History Museum for observation.

Having participated in many late winter and early spring surveys of salamander breeding ponds (when we searched for adults and egg masses) and early summer seines of those ponds (when we were looking for the larvae just before metamorphosing and leaving the ponds), I assumed all these species had adapted to Long Island’s fairly regular summer drought, and would have left the temporary pools of water before they completely dried out in early August. So I was surprised to learn that spotted salamanders were still in their larval form over the Labor Day weekend.

Other more knowledgeable naturalists with a keen interest in herps, including Chris Chapin and Andy Sabin, were not. Chris mentioned finding young, recently metamorphosed spotted and tiger salamanders in the Sag Harbor area in August. And he pointed out that this year’s unusual cold, wet spring and early summer could have delayed the transformation from aquatic larva to terrestrial adult.

Researchers in nearby Rhode Island found that the larvae’s development did not follow a rigid timeline. Although emigration from the vernal ponds began around mid-July and most juveniles were in the adjacent forest floor by mid-August most years, if food—tiny freshwater copepods and water fleas—was plentiful and water levels adequate, the larvae would prolong their metamorphosis, opting to leave the aquatic environment later in the year as larger, more robust terrestrial juveniles. In the case of a site fed by spring water that never completely froze or dried up, larvae would overwinter, delaying transformation until spring when they would exit the pond.

On the other hand, if pond water levels drop precipitously or food supply dwindles, the larvae can accelerate metamorphosis, averting potential disaster and emerging earlier as smaller juveniles.

In their terrestrial form, the salamanders occupy the leaf litter and subterranean passages made by burrowing organisms, consuming a wide variety of soil invertebrates: earthworms, slugs, beetles, spiders and insects. A newly transformed spotted salamander is approximately 2.5 inches in length. Juveniles spend several years beneath the forest floor before reaching sexual maturity—two years for males and three for females—and returning to the breeding pond.

Because of their fossorial habits, most researchers never encounter juveniles. And despite their size, up to 9 inches in length, and 10-year lifespan, most researchers only see the adults when they are in the breeding ponds in early spring. Their habit of remaining underground, along with tiger, marbled, and blue-spotted salamanders, gave rise to their group name: the mole salamanders.

For more information about spotted salamanders, visit the South Fork Natural History Museum in Bridgehampton, or the following website:

http://www.uri.edu/cels/nrs/paton/LH_spotted_sal.html.

Mike Bottini is a naturalist and author of The Southampton Press Trail Guide to the South Fork, Exploring East End Waters: A Natural History and Paddling Guide, and The Walking Dunes: East Hampton’s Hidden Treasure. Check www.peconic.org for Mike’s field naturalist classes.